Preparation of porous sulfur



United States Patent 3,326,639 PREPARATION OF POROUS SULFUR Richard L. Every and Ralph Leroy Grimsley, Ponca City, Okla, assignors to Continental Oil Company, Pouca 3,326,639 Patented June 20, 1967 isopropanol, butanol2, 2-methyl-propan-ol-1, 2-methylpropanol-Z, pentanol-2, Z-methyl-butanol-Z, and the .like. Also, polyalcohols such as glycol, glycerol and the like are operable so long as they are soluble in water.

City Okla" a corporation of Delaware 5 The gaseous sulfur compounds can be in the pure state,

N0 Drawing Filed 1, 1965 429,67 mixed or in admixture with a carrier gas such as sour 10 Clainm (CL 23.424) gas from a gas well, sulfur-containing gases from refining operations, sulfur-containing gases from sintering This invention relates to a method of preparing porous operations and the like. sulfur. I v 10 The degree of porosity is dependent upon a number In the .copending application of the inventors of this of independent factors. In general, it can be said the invention, filed Feb. 1, 1965, and having Ser. No. higher the pH, the greater the porosity. Also, the more 429,644, it is disclosed'that finely-divided sulfur can be dilution, the greater the porosity, and finally the more prepared by passing gaseous sulfur compounds, particustirring, the greater the porosity. The degree of porosity larly S0 in combination with H sand mercaptans, into is generally affected in that order. water containing a small amount of alcohol, e.g., 0.5 In general, the sulfur suspension will be in the range to 5 weight percent. of 50 to although higher and lower ratios are oper- 1\flVe haveb now fOllld that by furtherlftreatment, this itble. Tlhe pI7-I muszt be 1basil; agd, in1 2general, will vary su ur can e cast an set 0 a porous su ur mass. rom a out to pre era y to There are many usesfor such a porous sulfur. For 20 The acidic sulfur suspension can be made basic by the exanple i hthe materlial vlvollllldmake Zn eiilcellllent fillter use of zny basilc materfial such as lgdroxideshas wtglloas me 121. e materla 1s 1g t in weig t an as a ow strong asic sa ts pre erably NaO NH O or H thermal conductivity, thus'making it an ideal insulating will be used. However, Ba(OH) Ca(OH) and the like material. The sulfur can be cast in place or in blocks and are useful. placed. The amount of stirrin should be at least sufficient Porous sulfur has been prepared by heating sulfur past to obtain an homogeneous mixture, but this is not absoits melting point, introducing a foaming agent and alloW- lutely necessary. Stirring for 5 to 10 minutes appears to ing the sulfur to solidify. However, such method requires improve porosity, presumably because a small amount an extraneous a ent and high heat. of air is incorporated into the mixture; however we do It is, therefor; an object of this invention to provide not want to be bound by this theory.

a low cost, easily prepared porous sulfur. To further illustrate the invention, but not to be con- According to the broad concept of this invention, sulsidered limiting, the following examples are given. fur is suspended in an acidic media, sufficient base is added to make the media basic and thereafter the sus- Example I 3f pglngiicfr; is poured into a preformed mold and allowed to H28 and S02 were bubbled into a 2% ethyl alcohol solution in water. Sulfur in colloidal form began to pre- ACCOFdmI to one aspect of thls mveatwni a cipitate immediately. This was continued until the solusu sp mslon formed Preferably by Passmg tion contained approximately 25% sulfur solids. The taming H25 E of 502 W a mercaptar} an 40 initial pH was about 0.5. NaOH was added until the pH j soluuon Water Whemm the alcohol PWjSent was 11.5 while constantly stirring the solution. The stirso ution was our into re ormed mo e su ur suspension is preferably concentrated by allowing it to Set up in abofit 30 minuteg, and contained about 80% settle and decanting the clear liquid off. The solution is Voids. then made basic by addition of the basic material. Example H Resulting dissolved salts due to the neutralization reaction are then preferably flushed out. The resulting The above procedure was repeated except the solution mixture is then stirred and poured into suitable molds was poured into the mold immed1ately after the pH of where it solidifies as a solid porous sulfur. 11.5 was reached. The sulfur contained about The dissolved salts due to the neutralization of the 50 voids. acid are then flushed out with water as their presence Example III decreases the structural strength of the porous sulfur. v

In general, the greater the stirring and the higher the The g i i f g g pH, the greater will be the porosity. We have successt F fa p d p was fully prepared sulfur having porosity of from about 50 a out 6 Su ur con ame a on a v01 to about 80 percent void volume. As was stated in the Example IV previously mentioned invention, the normal alcohols are preferred such as methanol, ethanol, propanol, butanol, Several more runs were made wherein various pH pentanol and particularly those of 1 to 3 carbon atoms. levels were tested against porosity and surface area. The However, isomers of these alcohols are useful such as results are tabulated below.

Run No. Base 7 I 8 9 10 11 Porosity Area Porosity Area" Porosity Area" Porosity Area" Porosity Area 48.2 69.2 64.9 61.9 57.0 54, s 57. 0 0. 79 60.9 1. 30 60. 4 0. 1s 79. s 2. 63.0 63.3 0.91 51.3 0. 86 67. 7 0 78 70.4 o. 91 43. 0 43. 4 53. 3 54. 3 57. 9

*Area in square meters per gram.

by the addition of NaOH to the solution.

Example A poroussulfur was prepared as in Example I and I 2. The method of claim 1 wherein the pH is increased 3. The method of claim 1 wherein the pH is by the addition of KOH to the solution.

.4. The method of claim 1 wherein the pH is increased by the addition of NH OH to the solution.

increased 5. A method of preparing solid, porous sulfur which comprises preparing a suspension of finely-divided sulfur in aqueous media underacidic conditions, adding sufficient base to the resulting suspension to increase the pH to within therange 9 to 12, stirring the solution for a predetermined time, pouring the resulting basic solution into molds and allowing the solution to solidify.

6. A method of preparing solid porous sulfur which comprises preparing a suspension of finely-divided sulfur in an acidic aqueous media containing 1 to 5 weight percent alcohol, adjusting the concentration of suspended sulfur in suspension to a predetermined level, adding sufficient base to increase the pH to within the range 9 to 12, stirring the resulting basic suspension for a pre- 4' determined time, pouring the thus prepared suspension into" molds, 'and all'owing' the solution to solidify.

7. The method of claim 6 wherein said base is NaOH.

8. The method of claim 6 wherein said base is KOH.

9. The method of claim 6 wherein said base is NH OH.

10. A method of preparing solid porous sulfur which comprises a (a) passing a gas containing S0 and a second sulfurcontaining .gas selected from the group consisting of H 8 and mercaptans into an aqueous solution of 0.5 to 5 weight percent alcohol in water;

(b) adding sufficient base to the resulting sulfur suspension to raise the pH to at least 7;

(c) pouring the resulting suspension into a preformed mold; and

(d)- allowing the sulfur to solidify.

References v Cited UNITED STATES PATENTS 980,158 12/1910 Kaiser 106-86 X 1,995,545 3/1935 Leahy 23225 2/1937 Wieder 23-224 OTHER REFERENCES OSCAR R. VERTIZ, Primary Examiner.

A. GREIF, Assistant Examiner. 

1. A METHOD OF PREPARING POROUS SULFUR WHICH COMPRISES SUSPENDING FINELY-DIVIDED SULFUR IN AN AQUEOUS MEDIA UNDER ACIDIC CONDITIONS, ADDING SUFFICIENT BASE TO SAID AQUEOUS MEDIA TO INCREASE THE PH TO WITHIN THE RANGE OF 7 TO 12, POURING THE RESULTING SOLUTION INTO PREFORMED SHAPES AND ALLOWING THE SOLUTION TO SOLIDIFY. 